The use of x-ray diffraction techniques for measuring residual stresses in crystalline substances such as metal or ceramic materials is well-known. The general idea with the use of x-ray diffraction is to subject the material to the radiation of x-rays with the resulting sensed x-ray diffraction peak interpreted to arrive at a measurement of a strength related characteristic, e.g. stress, retained austenite, and hardness of the part material. Some x-ray diffraction instruments have an x-ray head that is moved about the part so that measurements can be taken across a sufficient number of positions on the part to obtain information therefrom.
For example, the x-ray diffraction head of some prior x-ray diffraction instruments have a depending collimator tube with a lower end through which x-rays are emitted toward a part being analyzed. The x-ray diffraction head is pivoted about an Ω axis and moved in an arcuate path around a χ axis during analysis of the part. The Ω and χ axes intersect perpendicular to one another at a distal end of the collimator tube. However, these prior x-ray diffraction instruments utilize complicated drive structures to provide the movement of the x-ray head about the χ and Ω axes. The complicated structures may limit the size of parts that can be analyzed by the x-ray diffraction instruments in order to provide the desired movement of the x-ray diffraction head about the χ and Ω axes.